Polyhedral azaborane chemistry. The establishment of members of the hypho-type family [(RH2N)B8H11NHR], where groups R are now other than ethyl

Abstract

The reaction of [B ₉ H ₁₃ (SMe ₂ )] with primary amines NH ₂ R to give eight-boron cluster species [(RH ₂ N)B ₈ H ₁₁ NHR] is not limited to the case where R = ethyl. We find that the n-butyl, isopropyl and tert-butyl analogues are also readily formed. The structural type is illustrated by a single-crystal X-ray diffraction analysis on the isopropyl member of the family. The reaction proceeds stepwise, via an initial ligand exchange on [B ₉ H ₁₃ (SMe ₂ )] to give [B ₉ H ₁₃ (NH ₂ R)], as confirmed by treatment of [B ₉ H ₁₃ (SMe ₂ )] with NH ₂ Bu ^t to give [B ₉ H ₁₃ (NH ₂ Bu ^t )] followed by treatment with Pr ⁱ H ₂ N to give the mixed species [(Pr ⁱ H ₂ N)B ₈ H ₁₁ NHBu ^t ], also confirmed by single-crystal X-ray work, and showing that the amine on the starting arachno-{B ₉ H ₁₃ } residue is the one that finishes in the more intimately bound bridging position.